1. Field of the Invention
The present invention relates to a correction method for a touch panel, more particularly to a coordinate information correction method for an optical touch panel.
2. Description of the Related Art
Conventional touch panels include resistive touch panels, capacitive touch panels, and optical touch panels. The resistive touch panel, compared to the capacitive touch panel, is less expensive but has a slower response.
One example of an optical touch panel uses an infrared LED module, which emits infrared beams, and photodetector pairs around a periphery of the touch panel for detecting an interruption in a pattern of the infrared beams. Another optical touch panel uses an infrared backlight module and at least two image sensors (CCD or CMOS sensor elements) placed around the periphery of the touch panel for detecting a shadow, which is produced by an object approaching the touch panel, in a light curtain region defined by the infrared backlight module so as to locate the object.
A conventional optical touch panel disclosed in U.S. Patent Application Publication No. 2009/0146972 teaches the use of a processor to determine distortion parameters of lenses during calibration for correcting pointer coordinate data associated with a position of the pointer relative to a touch surface. Since the techniques proposed therein adopt nonlinear equations, the solutions obtained are only approximations, and the calculations involved are relatively complicated.